Treatment of cream



June 4, 1935. F. G. CORNELL, JR

TREATMENT OF CREAM Filed Jan. 10, 1954 G 1 qVNTOR ATTORNEYS Patented June 4, 1935 l v I UNITED STATES PATENT OFFICE TREATMENT or CREAM Fritz G. Cornell, Jr., Mountain Lakes, N. .r.

Application January 10, 1934, Serial No. 706,029

- 16 Claims. (01. 9a-11) This invention relates to the treatment of ticularly at temperatures below its congealing cream to increase its viscosity, point butter fat becomes progressively susceptible In average commercial cream at normal atto agglomeration. Therefore as the cream cools, mospheric temperatures, butter fat is present in the butter fat globules impelled by the uniform the form of clusters of numerous closely adheror increased concussion are caused to become reing globules, which originally were suspended in clustered to an even greater extent than in raw the milk serum in a uniformly dispersed state, unpasteurized cream; consequently, the pasbut such natural, uniform dispersion was lost teurized cream reverts to a condition of nonbecause of agglomerating influences brought uniform fat dispersion and loses considerable of about through concussion applied to the cream its potential and very much desired high viscosity. 10 as it came in contact with numerous devices used An object of this invention is a, physicalproin its previous treatment, such as milking macedure by which the efiect of concussion imchine, pre-cooling machine, separating machine, parted to the cream during cooling is minimized transportation machine, etc. in order to obtain high final viscosity in the It has been observed that when cream is heatproduct. 15

ed, the butter fat clusters are caused to separate According to the present invention, the degree materially from each other with the result that of agitation to which the cream is subjected durmore uniform distribution of individual butter ing cooling, and also sometimes during heating, fat globules throughout the serum is obtained. is controlled and is regulated according to the This is particularly true during pasteurization characteristics of the cream, particularly its re- 20 of cream in which case the butter fat globules action to being benefited by such controlled agiagain assume a highly dispersed state, particu- 'tation. At temperatures used during pasteurizalarly at the high temperature required for eftion, cream is subjected to the usual and hereficient and satisfactory pasteurization. tofore ordinary degree of agitation. However, in

It is obvious that uniformly dispersed globular this case as the temperature of the cream drops, fat results in higher cream viscosity than would the speed of the agitator is materially reduced, be the case were the fat in the form of few but thereby decreasing the violence of agitation, large clusters. Thus the high pasteurizing temwhich inturn directly decreases the degree of perature produces a dispersed condition of the concussion to which the butter fat globules are fat which would be a desirable condition to resubjected. Decrease in the speed of the agitator tain in the cream after cooling with consequent is continued as the temperature of the cream higher viscosity than would be the case with drops until the final cooling temperature is non-uniform distribution of the t globules. reached. In cream cooled as above described, But heretofore in the heating and cooling rthe butter fat is more generally dispersed, and quired for the pasteurization of cream, it has not consequently the cream has a greater degree of been possible retain this desirable un flr viscosity thanisthe case where pasteurized cream dispersion of butter fat globules in the cream i a itated during cooling according to the prior after cooling. standard procedures.

l y, during batch pasteurization, ea is Other objects, novel features and advantages of heated and cool d by means of a moving agitflthis invention will be apparent from the follow- 40 tor, thrOllgh which a heating and then a cooling ing specification and accompanying drawing, fluid is passed in indirect heat-exchange relation wh rein the single figure discloses one form of to the cream, or he agitator may propel the apparatus for treating cream according to the cream against a fixed surface through which ininvention, direct heat relation exists with the cream; the A frame or box In constitutes a jacket for a a itat r in su as is u l p ated at vat H arran'gedwithin the frame and having a co Speed, or if at a varied speed. ts peed cover 42. A tubular shaft I3 is rotatably supis increased to offset or counteract the ordinary ported by the cover [2 and within the tubular increase in viscosity from cooling and consequent shaft [3 i arranged a, tube l4, B th th t b sl e is n 0f w due t r du tion of temperalar shaft l3 and the tube It project into and ture. This, however, subjects the fat globules to are rotatably supported by the head of a bracket substantial concussion. At temperatures above l5 which is carried by the cover l2. The bracket its melting point, butter fat is not particularly ,IB is provided with an outlet port l6 communisusceptible to agglomeration by concussion, but eating with the annular space between the tube at temperatures below its melting point and par- I4 and the tubular shaft l3 and with an inlet 55 port I! communicating with the upper end of the tube I4. and tube It are connected to a casting l8 having hollow radially extending arms 19 and 20 communicating respectively with the tube l4 and the space between shaft l3 and tube l4. A double coil 2| has one end extending into the arm l9 and the other end extending into the arm 20. Liquid passing through the inlet l1 flows down the pipe H through the arm l9 into one end of the coil, downwardly through one helix of the coil, upwardly through the other helix, through the arm 20 into the space between the shaft l3 and tube It, and out the port IS.

A bevel gear 22 is fixed to the shaft l3 and meshes with a pinion 23 which is driven by means of a motor 24 through suitable gearing (not shown). A tachometer 25 is driven by the motor and is calibrated to give direct reading of the number of revolutions per minute of the coil 2|.

A rheostat 26 is provided for controlling the speed of the motor 24, and if desired, may be so designed that various predetermined positions of the handle will result in different definite rotational speeds of the coil.

The apparatus above described may be advantageously used in practicing the invention, in which case a batch of cream is introduced into the vat II and steam or other heating medium is passed through the coil 2! which is rotated so as to agitate the cream while heating. During the heating operation the agitator may be rotated at a high or other desirable speed and its rotation so continued until the cream has been raised to the desirable pasteurizing temperature. A maximum speed of rotation is permissible above temperatures at which butter fat melts as it is not susceptible to agglomeration above such temperatures; consequently a relatively high speed of the agitator facilitates rapid transfer of heat to the cream. During the heating operation, a suitable heating medium may be passed through the jacket It! in heat exchange relation to the cream within the vat H to assist the agitator in heating the cream.

After pasteurization has been effected, the cream is cooled by rotation of the agitator and with suitable cooling medium passing through the coil 2 I, and suitable cooling medium is passed through the jacket in heat exchange relation to the cream in the vat I I. At the beginning of the cooling operation, the coil is-generally rotated at the same maximum speed used in final heating, for example, 33-R. P. M. or such lower speed as is found advisable. Such rotational speed is maintained during the first part of the cooling operation and continued until the temperature of the cream drops to that of approximately the melting point of butter fat. At such temperature just slightly above the melting point of butter fat, the rotational speed of the agitator is decreased to, say, 22-R. P. M., and the cooling operation continued until a. temperature is reached-that is approximately at the congealing point of butter fat, whereupon the speed of the coil is again decreased, this time, however, to approximately 11-R. P. M., which speed is maintained until the cream temperature reaches that of approximately 70 which is slightly above the temperature at which churning or agglomeration may be expected to commence. Consequently, at this stage of cooling, the speed of the agitator is still further reduced to approximately 'I-R. P. M.; thus still further decreasing the concussion to which the butter fat is subjected so as to minimize re- The lower ends of the shaft is.

clustering of fat which, if not prevented, destroys the dispersed condition of the fat globules, thereby causing loss of viscosity in the finished product. Later the coil speed is gradually decreased until sometimes it is reduced to as low as 2-R.P.M., particularly when cream is cooled to exceedingly low and unusual temperatures and also when it may be found that the cream is particularly susceptible to, churning tendencies. The temperature of the cooling medium may be dropped as the cooling proceeds or different cooling media by the above process has a viscosity almost equal to that of raw cream, whereas the ordinary proc-' esses materially reduce the viscosity of the processed cream below its orginal viscosity. In this new method of controlled agitation, the cooling operation does not appreciably alter the maximum dispersion of fat globules produced by the high temperature of pasteurization, a condition much desired but heretofore unobtainable. The concussion thru agitation is so controlled during the reduction of temperature as to be materially decreased even though and at the same time the butter fat becomes, with its acquiring of a lower temperature, more susceptible to agglomeration. v It is apparent that the above described cooling process is not limited to pasteurization. For example, already pasteurized and partially cooled cream to which starter may have been added for the development of acid and flavor prior to churning is held at a ripening temperature for a time determined by the degree of acid and aroma wanted. This process when completed is known as ripening of cream and must be followed by still further reduction of temperature to render the cream more favorable to churning. However, as the temperature decreases the susceptibility of the fat to pre-churning is very greatly increased, consequently the above method of controlling agitation in the vat during the final cooling just prior to introduction of the cream to the churn became very apparent as undesirable pre-churning afiects both the body and keeping quality of the butter.

The above described cooling process has been found to be essential for the development of viscosity in cream when advantage is to be taken of its colloidal properties in order to produce an abnormal thickening which it is desirable to fix at an approximately uniform amount by proper control and adjustment of agitation; more particularly in combination with a rapid and accurate adjustment of cooling medium temper: ature, especially at temperatures when the heated cream offers the maximum potential viscosity.

It is of course understood that the degree of concussion to which cream may be subjected to without setting up a ruinous degree of agglomeration of butter fat particles is at times altered by the natural characteristics of the fat which varies with the different breeds of cows, the feeds used, the period of lactation, and the season of the year and other factors. However, regardless of the individual and specific characteristics of any particular butter fat to be treated, its ultimate viscosity after heating for pasteurization will be materially increased by reducing and properly ad- Justing the total amount of concussion to which the cream is subjected during cooling more or stood that the treatment may be eflected with.

any other suitable type-apparatus. The agitator may be one having no provision for the pe of heating and cooling media, but which moves the cream into contact with a heated or cooled surface such as that provided by the wall of the vat in combination with the surrounding jacket.v

I claim:

1. The method or cooling heated cream which comprises passing cooling medium in heat exchange therewith, agitating the cream and controlling the degree of agitation in accordance with temperature decrease to minimize agglomeration of butter-tat globules.

2. The method of cooling cream which comprises passing cooling medium in heat exchange therewith, agitating the cream and reducing the degree of agitation in accordance with temperature decrease to, minimize agglomeration of butter fat globules.

3. The method of cooling heated cream which comprises passing cooling medium in heat exchange relation therewith, agitating the cream, controlling the temperature of the cream by progressively lowering the temperature of the cooling medium, adjusting the degreeot agitation of the cream in accordance with temperature decrease oi the cream to minimize agglomeration of butter fat globules.

4. The method of cooling heated cream which comprises passing cooling medium'into heat exchange relation therewith, agitating the cream, controlling the temperature of the cream by progressively lowering the temperature of the cooling medium, and reducing the degree of agitation of the cream in accordance with temperature decrease. thereof to minimize agglomeration of butter fat globules.

5. In the pasteurizationof cream, the method of cooling cream from pasteurization temperature which comprises passing cooling medium into heat exchange relation therewith, agitating the cream, and, at approximately the melting temperature of butter-fat, reducing the degree of agitation and progressively continuing such reduction in accordance with temperature decrease in the cream to minimize agglomeration of butterfat globules.

6. In the pasteurization of cream, the method of cooling cream from the temperature of pasteurization which comprises passing a cooling medium into heat exchange relation with the cream, agitating the cream, controlling the temperature of the cream by progressively lowering the temperature of the cooling medium, and, at approximately the melting temperature of butterfat, reducing the degree of agitation and progressively continuing such reduction as the temperature decreases in the cream to minimize agglomeration of butter fat globules.

'7. The method of cooling cream after pasteurization which comprises passing cooling medium in heat exchange relation therewith, simultaneously agitating the cream and simultaneoualy reducing the degree of agitation at approximately the melting temperature of butter i'at and at approximately the congealing temperature of butter fat.

8. The method of cooling cream, after pasteurization which comprises passing cooling medium.

in heat exchange therewith, simultaneously agitating the cream and progressively reducing the degree of agitation at approximately the melting temperature of butter-fat, at approximately the congealing temperature 01' butter-fat and at approximately churning temperature.

9. The method or cooling heated cream which comprises passing cooling medium in heat exchange therewith, agitating the cream and pro-' gressively reduclngthe degree of agitation according to temperature decrease and makingthe agitation reductions at more than one stage after the cream temperature reaches the optimum temperature conducive to clustering of butter- !at.

10. In the method of cooling cream wherein a batch is cooled by means of a moving agitator through which cooling medium is passed, the step which comprises reducing thev speed oi! the agitator in accordance with temperature decrease in the cream to minimize agglomeration of butter-fat globules.

11. In the method of cooling cream wherein a batch is cooled by means of a moving agitator through which cooling medium is passed, the steps which comprise controlling the temperature or the cream by progressively lowering the temperature of the cooling medium and reducing the speed of the agitator as the temperature decreases in the cream to minimize agglomeration of fat particles.

12. In the pasteurization of cream wherein a batch is'heated to pasteurizing temperature and then cooled by means of a moving agitator through which heating and cooling media are successively passed, the improved method which 13. In the pasteurization of cream wherein a.

batch is heated to pasteurizing temperature and then cooled by means of a moving agitator through which heating and cooling media are successively passed, the improved method of cooling which comprises initially operating the agitator at the same speed as during heating and, after the temperature drops. nearly to the melting point of butter-fat, progressively reducing the agitator speed in accordance with temperature decrease to avoid substantial agglomeration of butter-fat globules. 7

14. In the pasteurization of cream wherein a batch is heated to pasteurization temperature and then cooled by means of a moving agitator through which heating and cooling media are successively passed, the improved method of coolance with temperature decrease to minimize the agglomeration of butter-fat globules.

, 15. In the pasteurization of cream wherein a batch is heated to pasteurizing temperature and then cooled by means of a moving agitator through which heating and cooling media are successively passed. the improved method of cooling which comprises initially operating the agitator at the same speed as during heating and after the temperature drops substantially to the melting point of butter fat, reducing the agitator speed, and after the temperature drops, substan tiall'y to the congealing point of butter-fat, progressively reducing the agitator speed in accordance with temperature decrease to avoid substantial agglomeration of butter-fat globules.

16. In the pasteurization of cream wherein a batch is' heated to pasteurization temperature and then cooled by means of a moving agitator through which heating and cooling media are successively passed, the improved method 01' cooling which comprises initially operating the agitator at the same speed as during heating, controlling the temperature of the cream by progressively lowering the temperature of the cooling medium, and after the temperature drops substantially to the melting point of butter fat, reducing the agitator speed, and after the temperature drops substantially to the congealing point of butter fat, progressively reducing the agitator speed in accordance with temperature decrease to minimize agglomeration of butter fat globules.

FRITZ G. CORNELL, Ja. 

